Assessment of the occurrence and distribution of pharmaceuticals in a Mediterranean wetland (L'Albufera, Valencia, Spain) by LC-MS/MS.

The distribution of 17 pharmaceuticals between water and the solid phase (sediments and soils) was studied by utilizing solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Two extraction procedures for soils and sediments, prior to the SPE, one based on pressurized liquid extraction (PLE) with hot water and the other on methanol/water ultrasonic extraction, were compared. Absolute recoveries were 71.2-99.3% [relative standard deviation (RSD) <21.4%)] for water, and the method detection limits (MDLs) ranged from 0.3 to 10 ng L(-1). Recoveries were 35.4-105.3% (RSDs <19.1%) and 42.1-97.8% (RSDs <14%) for soil and sediment samples, respectively, using PLE and 20.2-86.5% (RSDs <25.1%) and 30.3-97.4% (RSDs <19.1%) using ultrasonic extraction. Fifteen of the 17 pharmaceuticals were present in the L'Albufera water at concentrations up to 17 μg L(-1). Oxytetracycline and tetracycline were not detected. In sediments, only tetracycline, norfloxacin and diclofenac were not found. The other studied pharmaceuticals were present in the range from less than the method quantification limit (MQL) to 35.83 ng g(-1). Among the 17 target compounds, ofloxacin, ciprofloxacin, norfloxacin, trimethoprim, clofibric acid and diclofenac were not detected in soil samples. The average concentrations ranged from less than the MQL for ibuprofen to 34.91 ng g(-1) for tetracycline. These results indicate that pharmaceuticals could survive the wastewater treatment processes, which could lead to their dissemination in water environments.